This invention generally relates to an implantable pump assembly for inflating a prosthesis. More particularly, the invention relates to a pump assembly for an inflatable penile prosthesis.
One common treatment for male erectile dysfunction is the implantation of a penile prosthesis. Such a prosthesis typically includes a pair of inflatable cylinders which are fluidly connected to a fluid (typically liquid) reservoir via a pump and valve assembly. The two cylinders are normally implanted into the corpus cavernosae of the patient and, in some embodiments, a reservoir may be implanted in the patient's abdomen. The pump assembly is implanted in the scrotum. During use, the patient actuates the pump and fluid is transferred from the reservoir through the pump and into the cylinders. This results in the inflation of the cylinders and thereby produces the desired penis rigidity for a normal erection. Then, when the patient desires to deflate the cylinders, a valve assembly within the pump is actuated in a manner such that the fluid in the cylinders is released back into the reservoir. This deflation then returns the penis to a flaccid state.
U.S. Pat. No. 4,566,446 discloses an implantable penile prosthesis comprising a fluid reservoir, a pump and elongate cylindrical prosthetic members. The pump includes an exterior surface with a plurality of circular ridges. The ridges are separated by grooves and extend around the exterior surface of the pump in a continuous, uninterrupted fashion. The device is operated by grasping the scrotal sac and squeezing the pumping section of the pump through the scrotal sac wall. The ridges of the pumping section are said to prevent the pumping section from slipping off the user's grasp during pumping. However, there is no structure blocking movement of tissue relative to the pump along a longitudinal axis of a groove.
U.S. Pat. No. 5,141,509 discloses an inflatable penile prosthesis. The prosthesis has an inflatable cylinder, a fluid reservoir, pump means and valves.
U.S. Pat. No. 4,437,457 discloses an improved pressure control valve for a medical device. U.S. Pat No. 4,682,583 discloses an artificial sphincter. The sphincter includes a pump, a housing and a node.
U.S. Pat. Nos. 4,537,183, 5,851,176 and 5,167,611 disclose penile prostheses with a pump and a plurality of circular ridges.
The Alpha I® Inflatable Penile Prosthesis was sold in the United States more than a year prior to the filing date of the present application by Mentor of Santa Barbara, Calif. The Alpha I Prosthesis included a pump assembly with a pump housing with release bars and a pump with a plurality of ridges that were separated by grooves that extended around the exterior surface of the pump in a continuous, uninterrupted fashion. To return the prosthesis to a flaccid state, the user was instructed to feel the protruding release bars and then squeeze them.
The continuous nature of the grooves and ridges is believed to present a problem. There is no structure to block movement of tissue along a direction substantially parallel to a longitudinal axis of a groove.
The ridges of the Alpha prosthesis are relatively thin and are spaced close together. Grooves between the ridges provide very little room for tissue to extrude into. This is undesirable as squeezing tissue into the grooves is believed to help anchor the pump to the tissue during the act of squeezing. FIG. 1A depicts ribs of a prior art Alpha device. One ridge was measured with an average width of about 0.024 inches and a depth of about 0.029 inches. The grooves tend to be somewhat small. One groove was measured with an average width of about 0.034 inches. FIG. 1A shows an area 1′ between ribs 2′ of a prior art Alpha prosthesis pump. This area was measured as 0.0012 square inches. There is very little area between the ribs 2′. This small area is not optimal for affording tissue to extrude between the ribs when the patients squeezes tissue to compress the pump bulb
The outer surfaces of the ridges of the Alpha I prosthesis tend to be rounded, with a large radius at the top. One radius was measured at 0.012 inches. This is also believed to be a problem as the rounded tips do not afford optimal tissue purchase and can result in tissue sliding off the tip of the ridge.
The Mark II® Inflatable Penile Prosthesis was sold in the United States more than a year prior to the filing date of the present application by Mentor of Santa Barbara, Calif. This device included a pump assembly including a resipump and a release ring.
The Mark II prosthesis has a single squeeze pump. The size of the pump limits the pressure that can be transmitted to the cylinders and therefore limits the stiffness of the cylinder. The Mark II cylinder is believed to afford a much less stiff cylinder than the Alpha I cylinder.
The release ring of the Mark II includes a plurality of ribs. Again, these ribs are rounded and slippery.